async_db: add WriterSink

app_async/src/main.rs

@@ -178,15 +178,11 @@ async fn db_writer_task(rx: UnboundedReceiver<Question>) {
     let mut writer: async_db::Writer<Question> =
         async_db::Writer::new(NEW_DB_FILENAME, writer_opts)
             .await
-            .expect("new db writer");
-
-    let mut stream: UnboundedReceiverStream<_> = rx.into();
-
-    writer
-        .load(&mut stream)
-        .await
-        .unwrap_or_else(|e| panic!("db writer load, {e:#?}"));
+            .unwrap_or_else(|e| panic!("db writer load, {e:#?}"));
 
+    let stream: UnboundedReceiverStream<_> = rx.into();
+    let stream = stream.map(Ok);
+    stream.forward(writer.sink()).await.expect("forward");
     writer.finish().await.expect("db writer finish");
 
     println!("write done");